WikiEducator, a wiki-based education community with a strong focus on developing countries, is the first production wiki to use LiquidThreads, a MediaWiki extension for threaded discussions. The project has a long and interesting history: three years ago, I reached the conclusion that regular wiki discussion pages were inadequate as a communication tool for many reasons, and wrote very basic specifications and created a mock-up for an alternative discussion system called LiquidThreads.
The core idea was to replace talk pages with discussion threads, which could be flexibly attached and re-attached to multiple different points in the wiki (hence the “liquidity”). Archiving was to be done automatically, but only if a summary had been created for a thread.
As these things go, it was merely an idea that would probably have been destined to be abandoned — until David McCabe picked it up and used it as a basis for a Summer of Code application in 2006. He demonstrated a fairly slick prototype at Wikimania 2006 (Hacking Days), but the project was on hold until Wikia and the Commonwealth of Learning joined forces to pay David for further work on it. I have played a project management role during this time. By now, LQT is still beta software, but it’s largely feature-complete.
It has turned out to be less liquid than we originally intended. It does not have the “one thread on multiple talk pages” feature, for one thing. It does implement the summary-based archiving, as well as page moves and a fairly cool message watchlist that replaces the “You have new messages”. Essentially you can get notified about any reply to threads you’ve been posting on — curently the notifications are shown on the watchlist, but David is working also showing a general notification for user talk messages.
There’ll be more debugging and usability work as we try this out with a real community, and the other major remaining step is to turn it into a proper MediaWiki extension (because it touches so many pieces of the code, it wasn’t possible to implement without touching the core codebase — we’ll have to get those hooks merged back into MW proper and get rid of anything idiosyncratic). After that, my hope is that it’ll be increasingly widely used as an alternative to talk pages, hopefully also on Wikimedia projects. With a basic framework like this in place, it’s now more realistic to think about things like in-wiki chat and e-mail-to-wiki gateways as well. All it really needs is a budget. If you’re interested in funding such projects, let me know.